From 64050cd1d2d30e3c16e73c7c7dd1a1c7df64f9aa Mon Sep 17 00:00:00 2001
From: Sebastian Mark <smark@posteo.net>
Date: Sat, 19 Oct 2024 10:08:54 +0200
Subject: [PATCH] feat: implement client start/stop commands
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

- add ClientCommand struct to handle incoming commands
- introduce timerStopChannel to manage timer stopping
- modify startTimer to return a boolean for success/failure
- update runPomodoroTimer to handle timer start/stop commands
- add start and stop buttons in the index.html for user interaction

🤖
---
 GoTomato.go | 110 ++++++++++++++++++++++++++++++++++++----------------
 index.html  |  47 +++++++++++++++++++++-
 2 files changed, 122 insertions(+), 35 deletions(-)

diff --git a/GoTomato.go b/GoTomato.go
index 374f5c9..28a0917 100644
--- a/GoTomato.go
+++ b/GoTomato.go
@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"log"
 	"net/http"
+	"sync"
 	"time"
 
 	"github.com/gorilla/websocket"
@@ -23,7 +24,14 @@ type BroadcastMessage struct {
 	TimeLeft   int    `json:"time_left"`
 }
 
+type ClientCommand struct {
+	Command string `json:"command"`
+}
+
 var clients = make(map[*websocket.Conn]bool)
+var timerRunning bool
+var timerStopChannel = make(chan bool, 1)
+var mu sync.Mutex // to synchronize access to shared state
 
 // broadcastMessage sends the remaining time to all connected clients.
 func broadcastMessage(message BroadcastMessage) {
@@ -38,37 +46,54 @@ func broadcastMessage(message BroadcastMessage) {
 	}
 }
 
-// start a countdown and broadcast ever second
-func startTimer(remaining_seconds int, mode string, session int) {
-	for remaining_seconds > 0 {
-		broadcastMessage(BroadcastMessage{
-			Mode:       mode,
-			Session:    session,
-			MaxSession: sessions,
-			TimeLeft:   remaining_seconds,
-		})
-		time.Sleep(time.Second)
-		remaining_seconds--
-	}
-	// send final 0 timer
-	broadcastMessage(BroadcastMessage{
-		Mode:       mode,
-		Session:    1,
-		MaxSession: 4,
-		TimeLeft:   0,
-	})
-}
-
-// iterate the Pomodoro work/break sessions
-func runPomodoroTimer() {
-	for session := 1; session <= sessions; session++ {
-		startTimer(workDuration, "Work", session)
-		if session == sessions {
-			startTimer(longBreakDuration, "LongBreak", session)
-		} else {
-			startTimer(shortBreakDuration, "ShortBreak", session)
+// startTimer runs the countdown and broadcasts every second.
+func startTimer(remainingSeconds int, mode string, session int) bool {
+	for remainingSeconds > 0 {
+		select {
+		case <-timerStopChannel:
+			return false // Stop the timer if a stop command is received
+		default:
+			broadcastMessage(BroadcastMessage{
+				Mode:       mode,
+				Session:    session,
+				MaxSession: sessions,
+				TimeLeft:   remainingSeconds,
+			})
+			time.Sleep(time.Second)
+			remainingSeconds--
 		}
 	}
+	broadcastMessage(BroadcastMessage{
+		Mode:       mode,
+		Session:    session,
+		MaxSession: sessions,
+		TimeLeft:   0,
+	})
+	return true
+}
+
+// runPomodoroTimer iterates the Pomodoro work/break sessions.
+func runPomodoroTimer() {
+	mu.Lock()
+	timerRunning = true
+
+	for session := 1; session <= sessions; session++ {
+		if !startTimer(workDuration, "Work", session) {
+			break
+		}
+		if session == sessions {
+			if !startTimer(longBreakDuration, "LongBreak", session) {
+				break
+			}
+		} else {
+			if !startTimer(shortBreakDuration, "ShortBreak", session) {
+				break
+			}
+		}
+	}
+
+	timerRunning = false
+	mu.Unlock()
 }
 
 // upgrade HTTP requests to WebSocket connections.
@@ -88,23 +113,40 @@ func handleConnections(w http.ResponseWriter, r *http.Request) {
 	// Register the new client
 	clients[ws] = true
 
-	// Clean up when the client disconnects
+	// Listen for commands from this client
 	for {
-		_, _, err := ws.ReadMessage()
+		_, message, err := ws.ReadMessage()
 		if err != nil {
 			log.Printf("Client disconnected: %v", err)
 			delete(clients, ws)
 			break
 		}
+
+		// Handle incoming commands
+		var command ClientCommand
+		err = json.Unmarshal(message, &command)
+		if err != nil {
+			log.Printf("Error unmarshalling command: %v", err)
+			continue
+		}
+
+		// Process the commands
+		switch command.Command {
+		case "start":
+			if !timerRunning {
+				go runPomodoroTimer()
+			}
+		case "stop":
+			if timerRunning {
+				timerStopChannel <- true
+			}
+		}
 	}
 }
 
 func main() {
 	http.HandleFunc("/ws", handleConnections)
 
-	// Start a goroutine that runs the Pomodoro timer and broadcasts updates.
-	go runPomodoroTimer()
-
 	log.Println("Pomodoro WebSocket server started on :8080")
 	err := http.ListenAndServe(":8080", nil)
 	if err != nil {
diff --git a/index.html b/index.html
index a092d2f..58fa15c 100644
--- a/index.html
+++ b/index.html
@@ -5,22 +5,67 @@
 	<meta charset="UTF-8">
 	<meta name="viewport" content="width=device-width, initial-scale=1.0">
 	<title>Pomodoro Timer</title>
+	<style>
+		button {
+			padding: 10px 20px;
+			margin: 5px;
+			font-size: 16px;
+		}
+
+		#timer {
+			font-size: 24px;
+			margin-top: 20px;
+		}
+	</style>
 </head>
 
 <body>
 	<h1>Pomodoro Timer</h1>
 	<div id="timer">Connecting to server...</div>
 
+	<!-- Buttons to start and stop the timer -->
+	<button id="startButton">Start</button>
+	<button id="stopButton">Stop</button>
+
 	<script>
 		var ws = new WebSocket("ws://localhost:8080/ws");
 
+		ws.onopen = function () {
+			document.getElementById("timer").innerText = "Connected to server.";
+		};
+
+		// Handle incoming messages and update the timer display
 		ws.onmessage = function (event) {
-			document.getElementById("timer").innerText = event.data;
+			var data = JSON.parse(event.data);
+			var mode = data.mode;
+			var session = data.session;
+			var maxSession = data.max_session;
+			var timeLeft = data.time_left;
+
+			document.getElementById("timer").innerText =
+				mode + " Session " + session + "/" + maxSession + ": " + formatTime(timeLeft);
 		};
 
 		ws.onclose = function () {
 			document.getElementById("timer").innerText = "Connection closed.";
 		};
+
+		// Format time in MM:SS
+		function formatTime(seconds) {
+			var minutes = Math.floor(seconds / 60);
+			var remainingSeconds = seconds % 60;
+			return minutes.toString().padStart(2, '0') + ":" + remainingSeconds.toString().padStart(2, '0');
+		}
+
+		// Send start command to the server
+		document.getElementById("startButton").addEventListener("click", function () {
+			ws.send(JSON.stringify({command: "start"}));
+		});
+
+		// Send stop command to the server
+		document.getElementById("stopButton").addEventListener("click", function () {
+			ws.send(JSON.stringify({command: "stop"}));
+		});
 	</script>
 </body>